Enhanced radio resource control reestablishment procedure for cellular communication networks

Abstract

In accordance with an example aspect of the present disclosure, there is provided a method comprising: receiving, by an apparatus from a user equipment, a radio resource control message and information associated with a priority state of a radio resource control connection between the user equipment and a first radio network node; and determining, by the apparatus, whether to preferentially schedule, reject, establish or reestablish a radio resource control connection between the user equipment and the first radio network node or a radio resource control connection between the user equipment and the second radio network node based on at least the information associated with the priority status.

Description

Technical Field

[0001] Various example embodiments relate generally to cellular communication networks and, more particularly, to radio resource control re-establishment procedures in such networks. Background Art

[0002] The reestablishment process may be initiated by a user equipment UE to continue a radio resource control RRC connection when a fault condition occurs. The RRC connection reestablishment process may be used, for example, in various cellular communication networks, such as in a cellular communication network operating according to a 5G radio access technology. 5G radio access technology may also be referred to as new radio NR access technology. The third generation partnership project 3GPP has developed standards for 5G / NR. In general, it is necessary to provide enhanced methods, devices and computer programs related to the RRC connection reestablishment process in a cellular communication network. Such enhancements may also be beneficial in other wireless communication networks, such as in future 6G networks. Summary of the invention

[0003] According to some aspects, the subject matter of the independent claims is provided. Some example embodiments are defined in the dependent claims.

[0004] The scope of protection sought for various example embodiments of the present disclosure is set out by the independent claims. Example embodiments and features described in this specification that do not fall within the scope of the independent claims, if any, should be interpreted as examples that aid in understanding the various example embodiments of the present disclosure.

[0005] According to a first aspect of the present disclosure, there is provided an apparatus, comprising: at least one processor; and at least one memory storing instructions, wherein when the instructions are executed by the at least one processor, the apparatus at least: receives a radio resource control message from a user equipment and information associated with a priority status of a radio resource control connection between the user equipment and a first radio network node; and determines whether to prioritize, reject, establish or reestablish a radio resource control connection between the user equipment and the first radio network node or a radio resource control connection between the user equipment and a second radio network node based at least on the information associated with the priority status. The apparatus of the first aspect may be a radio network node or a control device configured to control its functions when installed therein.

[0006] Example embodiments of the first aspect may include at least one feature from the following bulleted list or any combination of the following features: wherein said information associated with the priority status of the radio resource control connection between the user equipment and the first radio network node is received in an establishment cause or a restoration cause of a radio resource control message; wherein the information associated with the priority status of the radio resource control connection between the user equipment and the first radio network node comprises a priority value of the radio resource control connection between the user equipment and the first radio network node; · wherein the priority value of the radio resource control connection between the user equipment and the first radio network node is low, medium, high or urgent; wherein said information associated with the priority status of the radio resource control connection between the user equipment and the first radio network node comprises a service value of the radio resource control connection between the user equipment and the first radio network node; · wherein the service value of the radio resource control connection between the user equipment and the first radio network node is low, normal, high priority mission critical service, multimedia priority service or emergency; wherein the radio resource control message is a radio resource control re-establishment request message or a radio resource control setup complete message, and the radio resource control message comprises said information associated with a priority status of a radio resource control connection between the user equipment and the first radio network node; wherein the logical channel identification indicates that the establishment cause field of the radio resource control message includes said information about the priority status; wherein the logical channel identifier indicates a priority status of a radio resource control connection between the user equipment and the first radio network node; · the instructions stored therein, when executed by the at least one processor, further cause the apparatus to at least: determine to establish or re-establish a radio resource control connection between the user equipment and the second radio network node when the second radio network node has resources available for the priority state; · the instructions stored therein, when executed by the at least one processor, further cause the apparatus to at least: determine not to establish or re-establish a radio resource control connection between the user equipment and the second radio network node when the second radio network node does not have resources available for the priority state; · the instructions stored therein, when executed by the at least one processor, further cause the apparatus to at least: send a configuration to the user equipment, the configuration configuring the user equipment to: send the information regarding the priority status upon determining that a radio resource control connection between the user equipment and the first radio network node has experienced a failure condition; • The instructions stored therein, when executed by at least one processor, further cause the apparatus to at least: send a response to a radio resource control message to a user equipment based on the determination.

[0007] According to a second aspect of the present disclosure, there is provided an apparatus, comprising: at least one processor; and at least one memory storing instructions, wherein when the instructions are executed by the at least one processor, the apparatus at least: determines that a radio resource control connection between the apparatus and a first radio network node has a fault condition; and after the determination, sends a radio resource control message and information associated with a priority state of the radio resource control connection between the apparatus and the first radio network node to the first radio network node or the second radio network node. The apparatus of the second aspect may be a user equipment or a control device configured to control its function when installed therein.

[0008] Example embodiments of the second aspect may include at least one feature from the following bulleted list or any combination of the following features: · wherein the stored instructions, when executed by at least one processor, further cause the apparatus to at least: establish a radio resource control connection between the apparatus and a first radio network node; and store said information associated with a priority status of the radio resource control connection between the user equipment and the first radio network node to at least one memory of the apparatus; · wherein the stored instructions, when executed by the at least one processor, further cause the apparatus to at least: store the information to at least one memory of the apparatus based on an establishment cause or a resumption cause of a radio resource control message sent by the apparatus to the first radio network node during a radio resource control connection between the apparatus and the first radio network node; · the instructions stored therein, when executed by the at least one processor, further cause the apparatus to at least: send, in an establishment cause or a restoration cause of a radio resource control message, said information associated with a priority status of a radio resource control connection between the apparatus and the first radio network node; wherein the information associated with the priority status of the radio resource control connection between the apparatus and the first radio network node comprises a priority value of the radio resource control connection between the apparatus and the first radio network node; · wherein the priority value of the radio resource control connection between the device and the first radio network node is low, medium, high or urgent; wherein the information associated with the priority status of the radio resource control connection between the apparatus and the first radio network node comprises a service value of the radio resource control connection between the apparatus and the first radio network node; wherein a service value of the radio resource control connection between the device and the first radio network node is normal, mission critical service, multimedia priority service, or emergency; wherein the radio resource control message is a radio resource control re-establishment request message or a radio resource control setup complete message, and the radio resource control message comprises said information associated with a priority status of the radio resource control connection between the user equipment and the first radio network node; wherein the logical channel identification indicates that the establishment cause field of the radio resource control message includes said information about the priority status; wherein the logical channel identification indicates said information associated with a priority status of a radio resource control connection between the user equipment and the first radio network node; · wherein the stored instructions, when executed by at least one processor, further cause the apparatus to at least: receive a configuration from a network, the configuration configuring the user equipment to: after determining that a fault condition has occurred, transmit said information regarding the priority status; • The instructions stored therein, when executed by the at least one processor, further cause the apparatus to at least: receive a response to the radio resource control message from the first radio network node or the second radio network node.

[0009] According to a third aspect of the present disclosure, there is provided an apparatus, comprising: a component for receiving a radio resource control message and information associated with a priority status of a radio resource control connection between the user equipment and a first radio network node from a user equipment; and a component for determining whether to prioritize, reject, establish or reestablish a radio resource control connection between the user equipment and the first radio network node or a radio resource control connection between the user equipment and a second radio network node based at least on the information associated with the priority status. The apparatus of the third aspect may be a radio network node or a control device configured to control its functions when installed therein.

[0010] A fourth aspect of the fundamental disclosure provides an apparatus, comprising: a component for determining that a radio resource control connection between the apparatus and a first radio network node has experienced a fault condition; and a component for sending a radio resource control message and information associated with a priority state of the radio resource control connection between the apparatus and the first radio network node to the first radio network node or the second radio network node after the determination. The apparatus of the fourth aspect may be a user equipment or a control device configured to control its function when installed therein.

[0011] According to a fifth aspect, a first method is provided, comprising: receiving, by a device, a radio resource control message from a user equipment and information associated with a priority status of a radio resource control connection between the user equipment and a first radio network node; and determining, by the device, at least based on the information associated with the priority status, whether to prioritize, reject, establish or reestablish a radio resource control connection between the user equipment and the first radio network node or a radio resource control connection between the user equipment and a second radio network node. The first aspect may be performed by a radio network node or a control device configured to control its function when installed therein. That is, the device of the first method may be a radio network node or a control device configured to control its function when installed therein.

[0012] According to a fourth aspect, a second method is provided, comprising: determining, by a device, that a radio resource control connection between the device and a first radio network node has experienced a fault condition; and, after the determination, sending, by the device, a radio resource control message and information associated with a priority state of the radio resource control connection between the device and the first radio network node to the first radio network node or the second radio network node. The second aspect may be performed by a user device or a control device configured to control a function thereof when installed therein. That is, the device of the first method may be a user device or a control device configured to control a function thereof when installed therein.

[0013] According to a seventh aspect of the present disclosure, there is provided a non-transitory computer-readable medium having a computer-readable instruction set stored thereon, which, when executed by at least one processor, causes a device to at least perform a first method. According to an eighth aspect of the present disclosure, there is provided a non-transitory computer-readable medium having a computer-readable instruction set stored thereon, which, when executed by at least one processor, causes a device to at least perform a second method.

[0014] According to a ninth aspect of the present disclosure, there is provided a computer program, comprising instructions, which, when executed by a device, cause the device to perform a first method. According to a tenth aspect of the present disclosure, there is provided a computer program, comprising instructions, which, when executed by a device, cause the device to perform a second method. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 illustrates examples of network scenarios according to at least some example embodiments;

[0016] Figure 2 A first signaling diagram is shown according to at least some example embodiments;

[0017] Figure 3showing a second signaling diagram according to at least some example embodiments;

[0018] Figure 4 shows a third signaling diagram according to at least some example embodiments;

[0019] Figure 5 An example apparatus capable of supporting at least some example embodiments is shown;

[0020] Figure 6 A flow chart of a first method according to at least some example embodiments is shown. DETAILED DESCRIPTION

[0021] At least for various cellular communication networks, the radio resource control RRC connection reestablishment process can be enhanced by the process described herein. More specifically, the RRC connection reestablishment process can be enhanced in the following manner: the user equipment UE can provide information associated with the priority state of the RRC connection between the UE and the first radio network node after determining that a failure condition has occurred in the RRC connection between the UE and the first radio network node.

[0022] The UE may send said information associated with the priority status of the RRC connection between the UE and the first radio network node to the first radio network node or the second radio network node, so that the receiving radio network node may, for example, consider said information when determining whether to prioritize, reject, establish or reestablish the RRC connection between the UE and the receiving radio network node. Thus, the receiving radio network node may ensure that, for example, a prioritized RRC reestablishment request is accepted when prioritized resources are available, even if normal resources will not be available, thereby enhancing the RRC connection reestablishment process. The receiving radio network node may be the first radio network node or the second radio network node.

[0023] Figure 1 Examples of network scenarios according to at least some example embodiments are shown. Figure 1 In an example scenario, there may be a cellular communication system including a UE 110, a first radio network node 120, a second radio network node 122, and a core network element 130. The UE 110 may be connected to the first radio network node 120 via an air interface 115, but after determining that a failure condition has occurred on the RRC connection between the UE 110 and the first radio network node 120, the UE 110 may initiate an RRC connection re-establishment procedure with the second radio network node 122 over the air interface 115. Alternatively, the UE 110 may initiate an RRC connection re-establishment procedure with the first radio network node 120 over the air interface 115. In some example embodiments, the air interface 115 may be a beam-based air interface.

[0024] UE 110 may include, for example, a smartphone, a cellular phone, a machine-to-machine M2M node, a machine type communication MTC node, an Internet of Things IoT node, an automobile telemetry unit, a laptop computer, a tablet computer, or virtually any kind of suitable wireless terminal. Radio network node 120 may be considered a last serving node for UE 110, and one cell of radio network node 120 may be the last serving cell for UE 110 before the fault condition occurs.

[0025] The air interface 115 between the UE 110 and the radio network nodes 120, 122 may be configured according to a radio access technology RAT, wherein both the UE 110 and the radio network nodes 120, 122 are configured to support the RAT. Examples of cellular RATs include Long Term Evolution LTE, New Radio NR (which may also be referred to as fifth generation 5G radio access technology), and MulteFire. For example, the UE 110 and the radio network nodes 120, 122 may be configured to operate according to at least one Third Generation Partnership Project 3GPP standard.

[0026] For example, in the context of LTE, the radio network nodes 120, 122 may be referred to as eNBs, while in the context of NR, the radio network nodes 120, 122 may be referred to as gNBs. The radio network nodes 120, 122 may generally be referred to as base stations, base station nodes, or radio access nodes. In some example embodiments, the radio network nodes 120, 122 may be referred to as transmit and receive points TRPs, or control multiple TRPs that may be co-located or non-co-located. In any case, the example embodiments of the present disclosure are not limited to any particular wireless technology. Instead, the example embodiments may be utilized in any wireless communication system that uses an RRC reestablishment procedure.

[0027] The radio network node 120 may be connected to the core network 130 directly or via at least one intermediate node via the interface 125. The core network 130 may include, for example, an access and mobility management function AMF. The core network 130 may also be connected to another network ( Figure 1 The wireless network nodes 120 and 122 may be coupled to the core network 130 or to another core network directly or via at least one intermediate node.

[0028] Figure 2 A first signaling diagram according to at least some example embodiments is shown. On the vertical axis, from left to right, there are Figure 1 The UE 110, the second radio network node 122, the first radio network node 120 and the core network 130. The core network 130 may specifically refer to the AMF. Time moves from the top to the bottom.

[0029] At step 202 , the UE 110 may be in an RRC connected state (RRC_CONNECTED) and possibly also in a connection management CM connected state (CM-CONNECTED) At step 202 , the UE 110 may have an ongoing RRC connection with the first radio network node 120 .

[0030] At step 204, the UE 110 may initiate an RRC reestablishment procedure to continue the RRC connection after determining that a failure condition (e.g., radio link failure, reconfiguration failure, integrity check failure, etc.) has occurred on the RRC connection between the UE 110 and the first radio network node 120. At step 204, the UE 110 may initiate the RRC reestablishment procedure by sending an RRC message (such as an RRC reestablishment request message (RRCReestablishmentRequest)) to the second radio network node 122. The UE 110 may, for example, send identification information about the first radio network node 120 where the failure condition for reestablishment has occurred, such as a physical cell identifier PCI and / or a cell radio network temporary identifier C-RNTI.

[0031] At step 206, if the UE context of UE 110 is not locally available at the second radio network node 122, the second radio network node 122 may request the first radio network node 120 (i.e., the last serving radio network node) to provide the UE context of UE 110. For example, at step 206, the second radio network node 122 may send a UE context retrieval request to the first radio network node 120. At step 208, the first radio network node 120 may respond by sending the UE context of UE 110 to the second radio network node 122. The first radio network node 120 may, for example, send a UE context retrieval response at step 208. The UE context of UE 110 may include necessary information required to maintain, for example, an E-UTRAN service to UE 110. The UE context of UE 110 may be established when a transition to an active state of UE 110 is completed or after handover resource allocation is completed during handover preparation. UE state information, security information, UE capability information, and / or an identification of a logical S1 connection associated with the UE may be included in the UE context.

[0032] Steps 210a and 212a may be for RRC reestablishment, and second radio network node 122 may use these steps to continue reestablishment of the RRC connection. At step 210a, second radio network node 122 may send an RRC reestablishment message (RRCRestablishment) to UE 110. In some example embodiments, the RRC reestablishment message may be sent on signaling radio bearer 1 (SRB1). At step 212a, UE 110 may respond by sending an RRC reestablishment complete message (RRCReestablishmentComplete) to second radio network node 122.

[0033] Steps 210b and 212b may be for reconfiguration, and when the RRC reestablishment process is ongoing, the second radio network node 122 may use these steps to perform reconfiguration to reestablish SRB2 and data radio bearer DRB. At step 210b, the second radio network node 122 may send an RRC reconfiguration message (RRCReconfiguration) to the UE 110. At step 212b, the UE 110 may respond by sending an RRC reconfiguration completion message (RRCReconfigurationComplete) to the second radio network node 122.

[0034] At step 214, the second radio network node 122 may send its forwarding address to the first radio network node 120. For example, if the loss of users buffered at the first radio network node 120 should be prevented, the second radio network node 122 may send its forwarding address (e.g., XN-U address indication) to the first radio network node 120. At step 216, the first radio network node 120 may respond by sending the sequence number SN status of the UE 110 to the second radio network node. For example, the first radio network node 120 may send an SN status transmission message to the second radio network node 122. In some example embodiments, the SN may be per DRB. For example, the SN may be a packet data convergence protocol PDCP, an SN of a first lost service data unit SDU, and optionally a status of the PDCP SDU.

[0035] At steps 218 and 220, the second radio network node 122 may perform a path switch for the UE 110. For example, the second radio network node 122 may send a path switch request to the core network 130, such as to the AMF of the core network 130, at step 218. At step 220, a path switch request response may be sent from the core network 130 to the second radio network node 122. For example, the path switch request response may be sent by the AMF.

[0036] At step 222, the second radio network node 122 may release the UE context of the UE 110 from the first radio network node 120. For example, the second radio network node 122 may send a UE context release message to the first radio network node 120, and the first radio network node 120 may release the UE context of the UE 110 after receiving the UE context release message.

[0037] Figure 3 A second signaling diagram according to at least some example embodiments is shown. On the vertical axis, from left to right, there are Figure 1 UE 110 and radio network node 122. Radio network node 122 may generally refer to a network. Time progresses from top to bottom.

[0038] If the network is able to find and verify a valid UE context for UE 110, then the RRC connection reestablishment may be considered successful. Alternatively, if the UE context for UE 110 cannot be retrieved, then an RRC establishment procedure may be performed, such as Figure 3 shown.

[0039] At step 302, the UE 110 may send an RRC reestablishment request message (RRCRestablishmentRequest) to the second radio network node 122 after determining that, for example, a failure condition has occurred on the RRC connection between the UE 110 and the first radio network node 120. At step 304, the second radio network node 122 may respond to the RRC reestablishment request message by sending an RRC setup message (RRCSetup) to the UE 110. At step 306, the UE 110 may respond to the RRC setup message by sending an RRC setup complete message (RRCSetupComplete).

[0040] Generally, problems may arise when a failure condition (e.g., radio link failure, reconfiguration failure, integrity check failure, etc.) has occurred during a high priority connection (e.g., an emergency call). If the second radio network node 122 (with which the UE 110 is establishing or reestablishing an RRC connection) cannot retrieve the UE context of the UE 110 from the first radio network node 120 (the last serving node of the UE 110, e.g., the old / source gNB), the second radio network node 122 will not know the priority status of the attempted reestablishment. For example, in a high load scenario, if the priority status of the RRC reestablishment request is due to a lack of normal resources if the priority status cannot be retrieved, the RRC reestablishment request may be fallen back to connection establishment, even if the prioritized resources would be available.

[0041] For example, in a congested situation, a non-prioritized RRC reestablishment request may result in the release of the UE context of the UE 100 due to a lack of normal resources, whereas in reality, prioritized resources are still available if, for example, information about the priority state of the previous RRC connection is unknown based on the RRC reestablishment request message. In this case, if there is no RRC establishment cause or similar information element (IE) that may indicate the priority of the call, the request will be erroneously downgraded and only the failure cause will be provided to the network.

[0042] Thus, example embodiments of the present disclosure enhance the RRC connection reestablishment procedure by enabling the UE 110 to provide information associated with a priority status of the RRC connection between the UE 110 and the first radio network node 120 to the second radio network node 122. The UE 110 may provide the information after a failure condition has occurred on the RRC connection between the UE 110 and the first radio network node 120. In general, the information associated with the priority status of the RRC connection between the UE 110 and the first radio network node 120 may indicate a priority level, a priority value, or a priority status of the RRC connection between the UE 110 and the first radio network node 120.

[0043] In some example embodiments, UE 110 may indicate information about a previous connection in which the failure condition occurred to the network. UE 110 may indicate the information associated with the priority state of the RRC connection between UE 110 and first radio network node 120 to second radio network node 122, for example, after determining that a failure condition has occurred in the RRC connection between UE 110 and first radio network node 120. The RRC connection between UE 110 and first radio network node 120 may be referred to as a previous connection because it was ongoing before the failure condition occurred.

[0044] In some example embodiments, UE 110 may store the information associated with the priority state of the RRC connection between UE 110 and first radio network node 120, such as an establishment cause or a connection priority. UE 110 may store the information to its memory. UE 110 may store the information, for example, during an RRC establishment or RRC recovery procedure. UE 110 may then send the stored information to the network, for example, during an RRC reestablishment procedure.

[0045] In some example embodiments, the information associated with the priority status of the RRC connection between UE 110 and first radio network node 120 may include a priority value of the RRC connection between UE 110 and first radio network node 120. For example, the priority value of the RRC connection between UE 110 and first radio network node 120 may be low, medium, or high. That is, the information about the priority status of the previous connection may include information about whether the priority of the previous connection is low, medium, high, or urgent.

[0046] Alternatively, the information associated with the priority status of the RRC connection between the UE 110 and the first radio network node 120 may include a service value of the RRC connection between the UE 110 and the first radio network node 110. The service value of the RRC connection between the UE 110 and the first radio network node 120 may be low, normal, high priority access HPA, mission critical service MCS, multimedia priority service MPS, or emergency. That is, the information about the priority status of the previous connection may include information about whether the priority of the previous connection is low, normal, high priority, mission critical, multimedia priority service, or emergency.

[0047] In some example embodiments, the information about the priority status of the previous connection may include one or more of the following: Option 1: Normal, Emergency, High Priority Access, MPS Priority Access, MCS Priority Access (e.g., 3 bits); Option 2: Normal, Priority Access, Mission Critical, Urgent (e.g., 2 bits); Option 3: Normal, Special Service / Emergency (1 bit).

[0048] In some example embodiments, UE 110 may send said information associated with the priority state of the RRC connection between UE 110 and first radio network node 120 to second radio network node 122 in an RRC message, such as an RRC Reestablishment Request message or an RRC Setup Complete message. The information may, for example, be in an Establishment Cause field of the RRC message. The information may, for example, be in an L3 Establishment Cause and thus be directly communicated to core network 130 for further prioritization. Thus, prioritization of the RRC connection may be enhanced.

[0049] Alternatively, the UE 110 may use a logical channel identifier LCID to indicate the priority status of the previous connection to the second radio network node 122. That is, the LCID may indicate the priority status of the RRC connection between the UE 110 and the first radio network node 120. For example, a dedicated common control channel CCCH, SDU LCID may be used for this purpose, i.e., an LCID for indicating a CCCH SDU, such as an RRC reestablishment request. The first radio network node 120 and / or the second radio network node 122 may be deployed in an architecture including a centralized unit and a distributed unit, wherein the distributed unit may process the L1 / MAC / RLC protocol, and the centralized unit may process the RRC. The LCID may be used to specify that the distributed unit is aware of the priority status and what the distributed unit should do with the priority status, thereby enhancing the prioritization of the RRC connection.

[0050] In some example embodiments, the LCID may be used to indicate that the establishment cause field of the RRC message includes the information about the priority state. For example, a dedicated CCCH SDU LCID indicating an RRC reestablishment request may be used to indicate that the RRC reestablishment cause carried in the RRC reestablishment request uses a different interpretation, for example, the interpretation from option 2 above.

[0051] In one embodiment, the network may configure the UE 110 to provide the information associated with the priority status of the RRC connection between the UE 110 and the first radio network node 120 during the RRC reestablishment procedure. For example, the second radio network node 122 may send a configuration to the UE 110 that configures the UE 110 to send the information about the priority status after determining that a failure condition has occurred in the RRC connection between the UE 110 and the first radio network node 120. Alternatively, the first radio network node 120 or some other radio network node may configure the UE 110. The configuration may be performed using dedicated signaling during the RRC connection or by broadcast signaling (e.g., from a cell of the second radio network node 122 that is performing the RRC reestablishment procedure).

[0052] In some example embodiments, upon determining that a failure condition has occurred during a high priority connection (such as an emergency call), UE 110 may move to an idle state (RRC_IDLE). In this case, a new high priority connection may need to be started from scratch. That is, the RRC establishment procedure may be initiated by UE 110 by sending an RRC establishment request to second radio network node 122. In some example embodiments, in this case, UE 110 may be allowed to bypass the RRC reestablishment procedure and move to an idle state.

[0053] In some example embodiments, space may be limited in the RRC Reestablishment Request message and therefore the above optimization may be required. That is, it may not be possible to include the previous connection establishment cause etc. in the message.

[0054] Figure 4 A third signaling diagram according to at least some example embodiments is shown. Figure 1 1 , the second radio network node 122 and the first radio network node 120. Time progresses from top to bottom.

[0055] At step 402, UE 110 may send an RRC establishment or resumption request message to the first radio network node 120 to establish or resume an RRC connection between UE 110 and the first radio network node 120. The RRC establishment or resumption request message may include information associated with a priority state of the RRC connection between UE 110 and the first radio network node 120.

[0056] After sending the RRC establishment or resumption request message, the UE 110 may store the information associated with the priority status of the RRC connection between the UE 110 and the first radio network node 120 at step 404. At step 404, the UE 110 may store the establishment cause provided at step 402, for example.

[0057] At step 406, radio network node 120 may send an RRC setup or resume message to UE 110. At step 408, UE 110 may send an RRC setup or resume complete message to first radio network node 120. At step 410, an RRC connection between UE 110 and first radio network node 120 is ongoing. In some example embodiments, UE 110 may store the information to at least one memory of UE 110 based on an establishment cause or a resumption cause of an RRC message sent by UE 110 to first radio network node 120 during the RRC connection.

[0058] At step 412, UE 110 may determine that a failure condition (e.g., radio link failure, reconfiguration failure, integrity check failure) occurs or has occurred on the RRC connection between UE 110 and first radio network node 120. At step 414, UE 110 may send an RRC message to second radio network node 122 after the determination of step 412. Figure 4 In the example shown, the RRC message may be sent to the second radio network node 122 , but it should be noted that in some example embodiments, the RRC message may be sent to the first radio network node 120 .

[0059] The RRC message may include said information associated with the priority status of the RRC connection between the UE 110 and the first radio network node 120. That is, the RRC message may include said information associated with the priority status of the previous connection.

[0060] Thus, after a failure condition occurs, the second radio network node 122 may receive an RRC message and the information associated with the priority state of the RRC connection between the UE 110 and the first radio network node 120. In this example embodiment, the RRC message may be an RRC reestablishment message. The information may be in the RRC message or indicated by the LCID.

[0061] At step 416, the second radio network node 122 may use the information associated with the priority status of the RRC connection between the UE 110 and the first radio network node 120 to check whether the connection requested by the UE 110 can be accepted. The second radio network node 122 may determine whether to establish or re-establish the RRC connection between the UE 110 and the second radio network node 122 based at least on the information associated with the priority status. For example, when the second radio network node 122 has resources available for the priority status, the second radio network node 122 may determine to establish or re-establish the RRC connection between the UE 110 and the second radio network node 122. Alternatively, when the second radio network node 122 does not have resources available for the priority status, the second radio network node 122 may determine not to establish or re-establish the RRC connection between the UE 110 and the second radio network node 122.

[0062] In some example embodiments, second radio network node 122 may determine whether to prioritize or reject an RRC connection between UE 110 and second radio network node 122. Alternatively, if the RRC message is sent to first radio network node 120, first radio network node 120 may determine whether to prioritize, reject, establish or reestablish an RRC connection between UE 110 and first radio network node 120.

[0063] At step 418, second radio network node 122 may send a response to the RRC message, such as an RRC setup message. After receiving the response, UE 110 may send an RRC setup complete message to second radio network node 122 at step 420. Alternatively, if the RRC message is sent to first radio network node 120, first radio network node 120 may send a response to the RRC message. In some example embodiments, there may be no response. For example, if the information associated with the priority state is sent in the RRC setup complete message. Alternatively, there may be no response if the expiration of a timer at UE 110 is considered a rejection.

[0064] Although RRC messages and RRC connections are used as examples in the exemplary embodiments of the present disclosure, the exemplary embodiments may be applied to any messages and connections having similar or identical functions. That is, radio resource control may refer to RRC or any other term / feature having similar or identical functions.

[0065] Figure 5 An example apparatus capable of supporting at least some example embodiments is shown. A device 500 is shown, which may include, for example, a UE 110, a first radio network node 120, or a second radio network node 122, or a control device configured to control functions thereof when installed therein. A processor 510 is included in the device 500, which may include, for example, a single-core or multi-core processor, wherein a single-core processor includes one processing core and a multi-core processor includes more than one processing core. The processor 510 may generally include a control device. The processor 510 may include more than one processor. The processor 510 may be a control device. The processing core may include, for example, a Cortex-A8 processing core manufactured by ARM Holdings or a Steamroller processing core manufactured by Advanced MicroDevices Corporation. The processor 510 may include at least one Qualcomm Snapdragon and / or Intel Atom processor. The processor 510 may include at least one application specific integrated circuit ASIC. The processor 510 may include at least one field programmable gate array FPGA. The processor 510 may be a component for performing the method steps in the device 500. The processor 510 may be configured at least in part by computer instructions to perform actions.

[0066] The processor may include circuitry or be configured as one or more circuits configured to perform the various stages of the method according to the example embodiments described herein. As used in this application, the term "circuitry" may refer to one or more or all of the following: (a) hardware circuit implementations only, such as implementations in analog and / or digital circuits only, and (b) combinations of hardware circuits and software, such as (if applicable): (i) a combination of analog and / or digital hardware circuits with software / firmware, and (ii) any portion of a hardware processor with software (including a digital signal processor, software, and memory that work together to enable a device such as a mobile phone or server to perform various functions); and (c) hardware circuits and / or processors that require software (e.g., firmware) to operate, such as a microprocessor or a portion of a microprocessor, but the software may not be present when the software is not required for operation.

[0067] This definition of circuitry applies to all uses of the term in this application, including any claims. As another example, as used in this application, the term circuitry also covers an implementation of only a hardware circuit or processor (or multiple processors) or a portion of a hardware circuit or processor and its (or its) accompanying software and / or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in a server, cellular network device, or other computing or network device.

[0068] Device 500 may include memory 520. Memory 520 may include random access memory and / or permanent memory. Memory 520 may include at least one RAM chip. Memory 520 may include, for example, solid-state, magnetic, optical and / or holographic memory. Memory 520 may be at least partially accessible by processor 510. Memory 520 may be at least partially included in processor 510. Memory 520 may be a component for storing information. Memory 520 may include computer instructions, and processor 510 is configured to execute the computer instructions. When computer instructions configured to cause processor 510 to perform certain actions are stored in memory 520, and device 500 is generally configured to run under the guidance of processor 510 using computer instructions from memory 520, processor 510 and / or at least one processing core thereof may be considered to be configured to perform the certain actions. Memory 520 may be at least partially included in processor 510. Memory 520 may be at least partially external to device 500, but accessible by device 500.

[0069] The device 500 may include a transmitter 530. The device 500 may include a receiver 540. The transmitter 530 and the receiver 540 may be configured to transmit and receive information, respectively, according to at least one cellular or non-cellular standard. The transmitter 530 may include more than one transmitter. The receiver 540 may include more than one receiver. The transmitter 530 and / or the receiver 540 may be configured to operate according to, for example, the Global System for Mobile Communications GSM, Wideband Code Division Multiple Access WCDMA, Long Term Evolution LTE, and / or 5G / NR standards.

[0070] The device 500 may include a near field communication NFC transceiver 550. The NFC transceiver 550 may support at least one NFC technology, such as Bluetooth, Wibree, or similar technology.

[0071] The device 500 may include a user interface UI 560. The UI 560 may include at least one of a display, a keyboard, a touch screen, a vibrator arranged to signal a user by vibrating the device 500, a speaker, and a microphone. The user is able to operate the device 500 via the UI 560, for example to accept an incoming phone call, make a phone call or a video call, browse the Internet, manage digital files stored in the memory 520 or on a cloud accessible via the transmitter 530 and the receiver 540 or via the NFC transceiver 550, and / or play games.

[0072] The device 500 may include or be arranged to accept a user identification module 570. The user identification module 570 may include, for example, a subscriber identification module SIM card that may be installed in the device 500. The user identification module 570 may include information identifying a subscription of a user of the device 500. The user identification module 570 may include cryptographic information that may be used to verify the identity of the user of the device 500 and / or to facilitate encryption of transmitted information and billing of the user of the device 500 for communications enabled via the device 500.

[0073] The processor 510 may be equipped with a transmitter arranged to output information from the processor 510 to other devices included in the device 500 via electrical leads inside the device 500. Such a transmitter may include a serial bus transmitter, which is arranged to output information to the memory 520 for storage therein, for example, via at least one electrical lead. As an alternative to the serial bus, the transmitter may include a parallel bus transmitter. Similarly, the processor 510 may include a receiver, which is arranged to receive information in the processor 510 from other devices included in the device 500 via electrical leads inside the device 500. Such a receiver may include a serial bus receiver, which is arranged to receive information from the receiver 540, for example, via at least one electrical lead, for processing in the processor 510. As an alternative to the serial bus, the receiver may include a parallel bus receiver.

[0074] The device 500 may include Figure 5 Other devices not shown in the figure. For example, where the device 500 comprises a smart phone, it may include at least one digital camera. Some devices 500 may include a rear camera and a front camera, wherein the rear camera is intended for digital photography and the front camera is used for video telephony. The device 500 may include a fingerprint sensor arranged to at least partially authenticate a user of the device 500. In some example embodiments, the device 500 lacks at least one of the above devices. For example, some devices 500 may lack an NFC transceiver 550 and / or a user identification module 570.

[0075] The processor 510, the memory 520, the transmitter 530, the receiver 540, the NFC transceiver 550, the UI 560 and / or the user identification module 570 may be interconnected in a variety of different ways via electrical leads inside the device 500. For example, each of the above devices may be individually connected to a main bus inside the device 500 to allow the devices to exchange information. However, as will be appreciated by those skilled in the art, this is only an example, and various ways of interconnecting at least two of the aforementioned devices may be selected depending on the example embodiment without departing from the scope of the example embodiment.

[0076] Figure 6 1 is a flow chart of a first method according to at least some example embodiments. The apparatus of the first method may be the first radio network node 120 or the second radio network node 122, or a control device configured to control its functions when installed therein. That is, the steps of the first method may be performed by the first radio network node 120 or the second radio network node 122, or by a control device configured to control its functions when installed therein.

[0077] The first method may include: receiving, by the apparatus, a radio resource control message and information associated with a priority status of a radio resource control connection between the user equipment and the first radio network node from the user equipment at step 610. The first method may also include: determining, by the apparatus at step 620, whether to prioritize, reject, establish, or reestablish a radio resource control connection between the user equipment and the first radio network node or a radio resource control connection between the user equipment and the second radio network node based at least on the information associated with the priority status.

[0078] It should be understood that the disclosed example embodiments are not limited to the specific structures, process steps or materials disclosed herein, but extend to their equivalents, as will be understood by those of ordinary skill in the relevant art. It should also be understood that the terminology employed herein is only used for the purpose of describing specific example embodiments and is not intended to be limiting.

[0079] References throughout this specification to an exemplary embodiment or exemplary embodiments mean that a particular feature, structure, or characteristic described in conjunction with the exemplary embodiment is included in at least one exemplary embodiment. Thus, the phrases "in an exemplary embodiment" or "in an exemplary embodiment" appearing in various places throughout this specification do not necessarily all refer to the same exemplary embodiment. Where terms such as "about" or "substantially" are used to refer to a numerical value, the exact numerical value is also disclosed.

[0080] As used herein, for convenience, multiple items, structural elements, constituent elements and / or materials may be presented in a common list. However, these lists should be interpreted as if each member of the list is individually identified as a separate and unique member. Therefore, in the absence of contrary instructions, any individual member in the list should not be interpreted as a de facto equivalent of any other member in the same list based solely on their presentation in a common group. In addition, various example embodiments and examples may be mentioned in this article together with alternatives to their various components. It should be understood that such example embodiments, examples and alternatives should not be interpreted as actually equivalent to each other, but are considered to be separate and autonomous representations.

[0081] In an example embodiment, an apparatus such as the UE 110, the first radio network node 120 or the second radio network node 122 may include means for performing the above-described example embodiments and any combination thereof.

[0082] In an example embodiment, the computer program may be configured to cause a method according to the above-described example embodiments and any combination thereof. In an example embodiment, a computer program product embodied on a non-transitory computer readable medium may be configured to control a processor to perform a process including the above-described example embodiments and any combination thereof.

[0083] In an example embodiment, an apparatus such as the UE 110, the first radio network node 120, or the second radio network node 122 may include at least one processor and at least one memory storing instructions which, when executed by the at least one processor, cause the apparatus to perform at least the above example embodiments and any combination thereof.

[0084] In addition, the described features, structures or characteristics can be combined in any suitable manner in one or more example embodiments. In the foregoing description, many specific details, such as examples of length, width, shape, etc., are provided to provide a thorough understanding of the example embodiments of the present disclosure. However, those skilled in the relevant art will recognize that the present disclosure can be practiced without one or more specific details or using other methods, components, materials, etc. In other cases, well-known structures, materials or operations are not shown or described in detail to avoid obscuring various aspects of the present disclosure.

[0085] Although the foregoing examples are illustrative of the principles of example embodiments in one or more specific applications, it will be apparent to those skilled in the art that many modifications may be made to the form, usage, and details of implementation without exercising creative ability and without departing from the principles and concepts of the present disclosure. Therefore, it is not intended to limit the present disclosure except as set forth in the claims below.

[0086] The verbs "comprise" and "include" are used in this document as open limitations that neither exclude nor require the presence of unrecited features. Unless explicitly stated otherwise, the features recited in the dependent claims are mutually freely combinable. Furthermore, it is to be understood that the use of "a" or "an" (i.e. the singular) throughout this document does not exclude a plurality. Industrial Applicability

[0087] At least some example embodiments find industrial application in cellular communication networks, such as in 3GPP networks. List of abbreviations 3GPP Third Generation Partnership Project AMF Access and Mobility Management Function C-RNTI Cell Radio Network Temporary Identifier CCCH Common Control Channel CM Connection Management DRB Data Radio Bearer GSM Global System for Mobile Communications HPA High Priority Access LCID Logical Channel Identifier LTE Long Term Evolution M2M Machine to Machine MCS Mission Critical Services MPS Multimedia Priority Service NFC Near Field Communication PCI Physical Cell Identifier PDCP Packet Data Convergence Protocol RAT Radio Access Technology RRC Radio Resource Control SDU Service Data Unit SN Serial Number SRB Signalling Radio Bearer TRP Send and Receive Points UE User Equipment UL Uplink UI WCDMA Wideband Code Division Multiple Access WiMAX Worldwide Interoperability for Microwave Access WLAN Wireless Local Area Network Reference Signs List 110 UE 115 Air Interface 120,122 Wireless network node 125,135 Wired interface 130 Core Network 202-222 Figure 2 Steps in 302-306 Figure 3 Steps in 402-420 Figure 4 Steps in 500-570 Figure 5 The structure of the device 610-620 Figure 6 The first stage of the method

Claims

1. A device comprising: at least one processor; as well as at least one memory storing instructions, which, when executed by the at least one processor, cause the apparatus to at least: - receiving, from a user equipment, a radio resource control message and information associated with a priority status of a radio resource control connection between the user equipment and a first radio network node; as well as - determining whether to prioritize, reject, establish or re-establish the radio resource control connection between the user equipment and the first radio network node or the radio resource control connection between the user equipment and a second radio network node based at least on the information associated with the priority status.

2. The apparatus of claim 1, wherein the information associated with the priority status of the radio resource control connection between the user equipment and the first radio network node is received in an establishment cause or a resumption cause of the radio resource control message.

3. The apparatus according to claim 1 or claim 2, wherein the information associated with the priority state of the radio resource control connection between the user equipment and the first radio network node comprises a priority value of the radio resource control connection between the user equipment and the first radio network node. 4 . The apparatus according to claim 3 , wherein the priority value of the radio resource control connection between the user equipment and the first radio network node is low, medium, high or urgent.

5. The apparatus according to claim 1 or claim 2, wherein the information associated with the priority state of the radio resource control connection between the user equipment and the first radio network node comprises a service value of the radio resource control connection between the user equipment and the first radio network node.

6. The apparatus of claim 5, wherein the service value of the radio resource control connection between the user equipment and the first radio network node is low, normal, high priority mission critical service, multimedia priority service, or emergency.

7. An apparatus according to any one of the preceding claims, wherein the radio resource control message is a radio resource control re-establishment request message or a radio resource control setup complete message, and the radio resource control message includes the information associated with the priority state of the radio resource control connection between the user equipment and the first radio network node.

8. The apparatus according to any one of the preceding claims, wherein a logical channel identification indicates that an establishment cause field of the radio resource control message includes the information about the priority status.

9. The apparatus according to any one of claims 1 to 6, wherein a logical channel identification indicates the priority state of the radio resource control connection between the user equipment and the first radio network node.

10. The apparatus of any preceding claim, wherein the stored instructions, when executed by the at least one processor, further cause the apparatus to at least: - determining to establish or re-establish the radio resource control connection between the user equipment and the second radio network node when the second radio network node has resources available for the priority state.

11. The apparatus of any preceding claim, wherein the stored instructions, when executed by the at least one processor, further cause the apparatus to at least: - When the second radio network node has no resources available for the priority state, determining not to establish or not to re-establish the radio resource control connection between the user equipment and the second radio network node.

12. The apparatus of any preceding claim, wherein the stored instructions, when executed by the at least one processor, further cause the apparatus to at least: - sending a configuration to the user equipment, the configuration configuring the user equipment to send the information about the priority status after determining that a failure condition has occurred in the radio resource control connection between the user equipment and the first radio network node.

13. The apparatus of any preceding claim, wherein the stored instructions, when executed by the at least one processor, further cause the apparatus to at least: - Based on the determination, sending a response to the radio resource control message to the user equipment.

14. An apparatus comprising: at least one processor; as well as at least one memory storing instructions, which, when executed by the at least one processor, cause the apparatus to at least: - determining that a radio resource control connection between the apparatus and the first radio network node has experienced a failure condition; as well as - after said determining, sending a radio resource control message and information associated with a priority status of the radio resource control connection between the apparatus and the first radio network node to the first radio network node or the second radio network node.

15. The apparatus of claim 14, wherein the stored instructions, when executed by the at least one processor, further cause the apparatus to at least: - establishing the radio resource control connection between the apparatus and the first radio network node; and - storing said information associated with said priority status of said radio resource control connection between said user equipment and said first radio network node to said at least one memory of said apparatus.

16. The apparatus of claim 15, wherein the stored instructions, when executed by the at least one processor, further cause the apparatus to at least: - storing the information to the at least one memory of the apparatus based on an establishment cause or a resumption cause of a radio resource control message sent by the apparatus to the first radio network node during the radio resource control connection between the apparatus and the first radio network node.

17. The apparatus of claim 15 or 16, wherein the stored instructions, when executed by the at least one processor, further cause the apparatus to at least: - sending the information associated with the priority status of the radio resource control connection between the apparatus and the first radio network node in a setup cause or a resume cause of the radio resource control message.

18. The apparatus according to any one of claims 14 to 17, wherein the information associated with the priority state of the radio resource control connection between the apparatus and the first radio network node comprises a priority value of the radio resource control connection between the apparatus and the first radio network node.

19. The apparatus of claim 18, wherein the priority value of the radio resource control connection between the apparatus and the first radio network node is low, medium, high, or urgent.

20. The apparatus according to any one of claims 14 to 17, wherein the information associated with the priority status of the radio resource control connection between the apparatus and the first radio network node comprises a service value of the radio resource control connection between the apparatus and the first radio network node.

21. The apparatus of claim 20, wherein the service value of the radio resource control connection between the apparatus and the first radio network node is normal, mission critical service, multimedia priority service, or emergency.

22. An apparatus according to any one of claims 14 to 21, wherein the radio resource control message is a radio resource control re-establishment request message or a radio resource control setup complete message, and the radio resource control message includes the information associated with the priority state of the radio resource control connection between the user equipment and the first radio network node.

23. The apparatus according to any one of claims 14 to 22, wherein a logical channel identification indicates that an establishment cause field of the radio resource control message includes the information about the priority status.

24. The apparatus according to any one of claims 14 to 23, wherein a logical channel identification indicates the information associated with the priority status of the radio resource control connection between the user equipment and the first radio network node.

25. The apparatus of any one of claims 14 to 24, wherein the stored instructions, when executed by the at least one processor, further cause the apparatus to at least: - receiving a configuration from a network, said configuration configuring said user equipment to send said information about said priority status after determining that said fault condition has occurred.

26. The apparatus of any one of claims 14 to 25, wherein the stored instructions, when executed by the at least one processor, further cause the apparatus to at least: - receiving a response to the radio resource control message from the first radio network node or the second radio network node.

27. An apparatus comprising: - means for receiving, from a user equipment, a radio resource control message and information associated with a priority status of a radio resource control connection between the user equipment and a first radio network node; as well as - means for determining whether to prioritize, reject, establish or re-establish the radio resource control connection between the user equipment and the first radio network node or the radio resource control connection between the user equipment and a second radio network node based at least on the information associated with the priority status.

28. An apparatus comprising: - means for determining that a radio resource control connection between the apparatus and the first radio network node has experienced a failure condition; as well as - means for sending, after said determining, to said first or second radio network node a radio resource control message together with information associated with a priority status of said radio resource control connection between said apparatus and said first radio network node.

29. A method comprising: - receiving, by the apparatus, from a user equipment a radio resource control message and information associated with a priority status of a radio resource control connection between the user equipment and a first radio network node; as well as - determining, by the device at least based on the information associated with the priority status, whether to prioritize, reject, establish or re-establish the radio resource control connection between the user equipment and the first radio network node or the radio resource control connection between the user equipment and a second radio network node.

30. A method comprising: - determining, by the device, that a radio resource control connection between the device and the first radio network node has experienced a failure condition; as well as - sending, by the apparatus after the determining, a radio resource control message and information associated with a priority status of the radio resource control connection between the apparatus and the first radio network node to the first radio network node or the second radio network node.

31. A non-transitory computer readable medium having stored thereon a set of computer readable instructions, which when executed by at least one processor, cause an apparatus to at least perform: - receiving, from a user equipment, a radio resource control message and information associated with a priority status of a radio resource control connection between the user equipment and a first radio network node; and - determining whether to prioritize, reject, establish or re-establish the radio resource control connection between the user equipment and the first radio network node or the radio resource control connection between the user equipment and a second radio network node based at least on the information associated with the priority status.

32. A non-transitory computer readable medium having stored thereon a set of computer readable instructions, which when executed by at least one processor, cause an apparatus to at least perform: - determining that a radio resource control connection between the apparatus and the first radio network node has experienced a failure condition; and - after said determining, sending a radio resource control message and information associated with a priority status of the radio resource control connection between the apparatus and the first radio network node to the first radio network node or the second radio network node.

33. A computer program comprising instructions which, when executed by an apparatus, cause the apparatus to: - receiving, from a user equipment, a radio resource control message and information associated with a priority status of a radio resource control connection between the user equipment and a first radio network node; and - determining whether to prioritize, reject, establish or re-establish the radio resource control connection between the user equipment and the first radio network node or the radio resource control connection between the user equipment and a second radio network node based at least on the information associated with the priority status.

34. A computer program comprising instructions which, when executed by an apparatus, cause the apparatus to: - determining that a radio resource control connection between the apparatus and the first radio network node has experienced a failure condition; and - after said determining, sending a radio resource control message and information associated with a priority status of the radio resource control connection between the apparatus and the first radio network node to the first radio network node or the second radio network node.

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